Conventional collecting and condensing designs for electromagnetic radiation emphasize collecting and redirecting the maximum amount of light from a single point source radiating isotropically; in doing so, the ability of these designs to concentrate radiation flux into a small spot size is compromised. Adapting these designs to produce a small spot size results in a decrease in radiation flux because the emphasis of conventional designs (i.e. the collection and redirection of the maximum amount of light) conflicts with the goal of concentrating the light flux into the smallest possible spot size when the light originates from conventional incoherent light sources. Thus, small spot size images may be obtained only with a penalty in decreased flux density.
Currently two collecting and condensing designs are used. The first is a system of condenser lenses (See FIG. 1). Condenser lenses have several problems, including the creation of chromatic and spherical aberrations, the high cost of corrected optics, the inherent difficulty in aligning the lenses and the large amount of space the system demands. Ellipsoidal reflectors (FIG. 2.) are also used. Their problems include high cost and the unavoidable magnification of the image which reduces the flux density at the image. Both of these systems (FIGS. 1 and 2) tend to emphasize the collection and redirection of the maximum amount of light from a single point source. Thus, they fail to optimize both spot size and light density.
The invention optimizes these two fundamental optical characteristics to wit: spot size and energy. The invention is particularly useful where a small target (e.g. an optical fiber) needs to be illuminated with the highest possible density. For example, the invention may be used to couple a large amount of light from an arc lamp into a small single core optical fiber. Although similar results may be obtained by means of a conventional optical condenser arrangement, there are certain drawbacks of complexity and cost that are associated with such a conventional approach.